The present invention relates to a wire bonding method and apparatus for bonding a wire to a member to be bonded.
Generally, as a method of bonding a wire having a conducting portion which is not covered by covering material, there is adopted a so-called nailhead bonding method in which a ball is formed on an end of the wire and the ball is pressed on a pad from above by using a bonding head.
On the other hand, as shown in FIG. 8, when a wire 20 having a conducting portion 21 covered by a covering member 22 is bonded, the bonding head can not be used, therefore the above-mentioned method can not be used and a method as described in JP-A-2-101754, for example, is adopted.
In this bonding method, balls 23 are first formed at ends of the conducting portion 21 and the ball is held with a pincette by a worker to be put on a pad formed on a board. The ball 23 of the wire 20 is crushed in a moment by a bonding head having an end in which a flat surface is formed and is applied with ultrasonic waves to be heated so that the end of the wire is bonded on the pad.